Light-emitting device

Abstract

A light-emitting device includes a semiconductor epitaxial structure that has a first surface and a second surface, and that includes a first current spreading layer, a Inx1Ga1-x1As layer, a first cladding layer, an active layer and a second cladding layer disposed sequentially in such order from the first surface to the second surface, wherein, in the Inx1Ga1-x1As layer, 0<x1≤0.08. In another aspect of the disclosure, the first current spreading layer is made of gallium arsenide, and has a thickness ranging from 2 μm to 10 μm and a doping concentration ranging from 1E17/cm3 to 4E18/cm3. In yet another aspect of the disclosure, a layered stack is disposed between the first current spreading layer and the first cladding layer, and includes an Inx3Ga1-x3As layer and an Aly3Ga1-y3AszP1-z layer, in which 0.02<x3≤0.20, 0≤y3≤0.25, and 0.7<z≤0.95.

What is claimed is: 
     
         1 . A light-emitting device, comprising:
 a semiconductor epitaxial structure that has a first surface and a second surface opposite to said first surface, and that includes a first current spreading layer, a first In x1 Ga 1-x1 As layer, a first cladding layer, an active layer and a second cladding layer disposed sequentially in such order from said first surface to said second surface,   wherein, in said first In x1 Ga 1-x1 As layer, 0<x1≤0.08.   
     
     
         2 . The light-emitting device of  claim 1 , wherein said first In x1 Ga 1-x1 As layer has a thickness ranging from 100 nm to 1000 nm, and has a doping concentration ranging from 1E17/cm 3  to 4E18/cm 3 . 
     
     
         3 . The light-emitting device of  claim 1 , wherein said first current spreading layer has a composition represented by Al y1 Ga 1-y1 As, and 0≤y1≤0.25. 
     
     
         4 . The light-emitting device of  claim 3 , wherein said first current spreading layer has a thickness ranging from 2 μm to 10 μm, and has a doping concentration ranging from 1E17/cm 3  to 4E18/cm 3 . 
     
     
         5 . The light-emitting device of  claim 1 , wherein said semiconductor epitaxial structure further includes a first indium-containing transition layer that is disposed between said first current spreading layer and said first In x1 Ga 1-x1 As layer and that has an indium content which increases in a direction from said first current spreading layer to said first In x1 Ga 1-x1 As layer. 
     
     
         6 . The light-emitting device of  claim 5 , wherein the indium content of said first indium-containing transition layer increases in the direction from said first current spreading layer to said first In x1 Ga 1-x1 As layer in a linear manner. 
     
     
         7 . The light-emitting device of  claim 5 , wherein the indium content of said first indium-containing transition layer increases in the direction from said first current spreading layer to said first In x1 Ga 1-x1 As layer in a stepwise manner. 
     
     
         8 . The light-emitting device of  claim 1 , wherein said semiconductor epitaxial structure further includes a second current spreading layer that is disposed on said second cladding layer opposite to said active layer and that has a composition represented by Al y2 Ga 1-y2 As, and 0≤y2≤0.25. 
     
     
         9 . The light-emitting device of  claim 8 , wherein said second current spreading layer has a thickness that is greater than 0 μm and that is not greater than 3 μm, and has a doping concentration ranging from 1E17/cm 3  to 4E18/cm 3 . 
     
     
         10 . The light-emitting device of  claim 8 , wherein said semiconductor epitaxial structure further includes a second In x2 Ga 1-x2 As layer disposed between said second cladding layer and said second current spreading layer, and 0<x2≤0.08. 
     
     
         11 . The light-emitting device of  claim 10 , wherein said second In x2 Ga 1-x2 As layer has a thickness ranging from 100 nm to 1000 nm, and has a doping concentration ranging from 1E17/cm 3  to 4E18/cm 3 . 
     
     
         12 . The light-emitting device of  claim 10 , wherein said semiconductor epitaxial structure further includes a second indium-containing transition layer that is disposed between said second cladding layer and said second In x2 Ga 1-x2 As layer and that has an indium content which increases in a direction from said second cladding layer to said second In x2 Ga 1-x2 As layer. 
     
     
         13 . The light-emitting device of  claim 12 , wherein the indium content of said second indium transition layer increases in the direction from said second cladding layer to said second In x2 Ga 1-x2 As layer in a linear manner. 
     
     
         14 . The light-emitting device of  claim 12 , wherein the indium content of said second indium transition layer increases in the direction from said second cladding layer to said second In x2 Ga 1-x2 As layer in a stepwise manner. 
     
     
         15 . The light-emitting device of  claim 1 , wherein said light-emitting device emits invisible light having a peak wavelength ranging from 910 nm to 980 nm. 
     
     
         16 . A light-emitting device, comprising:
 a semiconductor epitaxial structure that has a first surface and a second first opposite to said first surface, and that includes a first current spreading layer, a first cladding layer, an active layer and a second cladding layer disposed sequentially in such order from said first surface to said second surface,   wherein, said first current spreading layer is made of gallium arsenide, has a thickness ranging from 2 μm to 10 μm, and has a doping concentration ranging from 1E17/cm 3  to 4E18/cm 3 .   
     
     
         17 . The light-emitting device of  claim 16 , wherein said semiconductor epitaxial structure further includes a second current spreading layer that is disposed on said second cladding layer opposite to said active layer, that is made of gallium arsenide, that has a thickness which is greater than 0 μm and which is not greater than 3 μm, and that has a doping concentration ranging from 1E17/cm 3  to 4E18/cm 3 . 
     
     
         18 . A light-emitting device, comprising:
 a semiconductor epitaxial structure that has a first surface and a second surface opposite to said first surface, and that includes a first current spreading layer, a layered stack, a first cladding layer, an active layer and a second cladding layer disposed sequentially in such order from said first surface to said second surface,   wherein said layered stack includes an In x3 Ga 1-x3 As layer and an Al y3 Ga 1-y3 As z P 1-z  layer, in which 0.02<x3≤0.20, 0≤y3≤0.25, and 0.7<z≤0.95.   
     
     
         19 . The light-emitting D device of  claim 18 , wherein said layered stack includes N pairs of said In x3 Ga 1-x3 As and Al y3 Ga 1-y3 As z P 1-z  layers that are alternately stacked on one another, and 2≤N≤20. 
     
     
         20 . The light-emitting device of  claim 19 , wherein each of said In x3 Ga 1-x3 As layers has a thickness ranging from 5 nm to 20 nm, and each of said Al y3 Ga 1-y3 As z P 1-z  layers has a thickness ranging from 5 nm to 50 nm.